It may set a record for the shortest tour of duty on a corporate board. Rambus ( RMBS) announced late Wednesday that Mark Pinto stepped down as a director, a mere 17 days after the company announced that he had joined the board. The company cited "corporate conflicts" that arose at Pinto's company which were not foreseeable at the time of his appointment. Pinto is the chief technology officer of semiconductor equipment maker Applied Materials ( AMAT). He also chairs Applied Material's venture investment committee. "While we regret his decision to withdraw from the board, we nevertheless defer to his judgment as to the need to do so," said Rambus chairman Geoff Tate in a statement. The move is highly unusual, particularly in today's compliance-focused corporate environment in which potential directors are carefully vetted for conflicts of interest by other board members. "I've never seen anything like that before," said one corporate lawyer in San Francisco who wished to remain anonymous. A spokesman at Applied Materials said Pinto's departure came after one of the company's customers voiced concern about Pinto serving on the Rambus board. The spokesman would not say which customer expressed the concern. Rambus, which licenses intellectual property relating to computer memory technology, is engaged in patent infringement litigation with numerous chipmakers including Micron ( MU), Samsung and Hynix Semiconductor. Investors have boosted Rambus shares more than 125% in the past three months in expectation of a positive outcome of the Hynix trial, which got under way earlier this month in federal court in San Jose, Calif. Shares of Rambus were up 0.68%, or 25 cents, at $37.03 in midday trading Thursday.